Chimney Diagrams

Glossary

Anchors are straps of steel that are secured into the bond beam and are tied back to the floor joists, roof rafters or wall members. The anchors tie the chimney to the house, which may provide support in the event of wind or earthquake.

Anchors are straps of steel that are secured into the bond beam and are tied back to the floor joists, roof rafters or wall members. The anchors tie the chimney to the house, which may provide support in the event of wind or earthquake.

Where referring to bricklaying and masonry chimneys, that connection between brick, stone or other masonry units formed by lapping them upon one another in carrying up the work, thereby forming an inseparable mass.

A member poured in the masonry at the support level of the chimney. The support level is usually at the floor and at the ceiling or roofline. It may also be above the roofline if the chimney is tall enough to require a supplementary support.

A chase is the chimney framework of either wood or metal studs. The chase cover is a galvanized sheet of metal fit to cover the chase and overhang the sides by 1/2-3/4”. Allowance of an inch air gap between the storm collar and the chase cover along with a 3/8” air space between the frame and cover established by spacers.

A natural by-product of burning wood. It can be defined as a combustible deposit, which originates as condensed wood smoke, including tar, vapors and other organic compounds. The physical appearance of these creosote deposits is usually dark brown or black in color and watery or tar-like depending on the mixture of tar and vapors and the amount of water vapor condensing.

In contrast with creosote, soot deposits are soft and black or brown in color, often mixed with fly ash.

A simple description is a ridge that extends from the back of the chimney to the slope of the roof. Usually found on chimneys wider than 30” with the purpose of shedding water away from the connection between the chimney and roof.

Chimney Safety Institute of America – CSIA is a non-profit, tax-exempt educational institution dedicated to chimney and venting system safety. CSIA is committed to the elimination of residential chimney fires, carbon monoxide intrusion and other chimney-related hazards that result in the loss of lives and property. To achieve its goals, CSIA devotes its resources to educating the public, chimney service professionals and other fire prevention specialists about the prevention and correction of chimney and venting system hazards.

A manufactured appliance furnished by the manufacturer as a single assembly or as a package set of subassemblies or parts, and including all the essential components necessary for it to function normally where installed as intended.

A chimney suitable for continuous use at 1000°F (538°C), composed of listed, factory-built components that might be fully enclosed in combustible, residential-type construction, and that is assembled in accordance with the terms of the listing to form the completed chimney.

Anchors are straps of steel that are secured into the bond beam and are tied back to the floor joists, roof rafters or wall members. The anchors tie the chimney to the house, which may provide support in the event of wind or earthquake.

Horizontal or vertical barriers intended to retard the spread of fire and hot gases between concealed areas. Firestopping shall be provided to cut off all concealed draft openings (both vertical and horizontal), and form an effective barrier between stories, and between a top story and roof space.

The noncombustible surfacing applied to the floor area extending in front of and at the sides of the hearth opening of a fireplace or a fireplace stove. Also where applied to the floor area beneath a fireplace stove or beneath an elevated overhanging fireplace hearth.

Equipment, materials, or services included in a list published by an organization acceptable to the authority having jurisdiction and concerned with evaluation of products or services that maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services and whose listing states either that the equipment, material, or service meets identified standards or has been tested and found suitable for specified purpose.

A simple description is a ridge that extends from the back of the chimney to the slope of the roof. Usually found on chimneys wider than 30” with the purpose of shedding water away from the connection between the chimney and roof.

Decorative structures commonly designed by architects and installed around the top of the chimney. Typically made from sheet metal or terra cotta materials, and often supported by plywood structures. Their purpose is aesthetics, not functional. Shrouds may cause heat to transfer to the wood frame of a chimney chase, allow heat and smoke to affect the thermo siphoning system (cooling) or potentially affect the draw of the system.

The transitional area from the damper opening to the beginning of the flue liner in a fireplace system.

The smoke chamber acts as a funnel to compress the smoke and gases from the fire so that they will squeeze into the chimney flue above. The smoke chamber is important for good draft action. It should be symmetrical in shape so that the draft pulls evenly on the fire in the firebox. The smoke chamber should be centered with the flue directly above the fireplace and its walls should be sloped at the same angle to provide even draft from the firebox to the chimney.

A smoke shelf is located at the bottom of the smoke chamber behind the damper and can collect soot and also gather any rain water that runs down the chimney. A smoke shelf improves draft conditions in a chimney and help eliminates downdrafts.

A procedure for ascertaining the tightness of a chimney and for detecting any cracks in a masonry chimney flue or deterioration or breaks in the integrity of a factory-built or metal chimney flue. The procedure involves igniting a smoke bomb or building a smoky fire in a fireplace or solid fuel-burning appliance, covering the chimney termination and checking for smoke leakage through the chimney walls.

A manufactured or field-constructed chimney intended only for non-residential applications having one or more metal walls, or made of metal with a refractory lining, and that is capable of withstanding the flue gas conditions of its use.